As offshore operators get into deeper waters and develop more mature oil and gas fields using more complex well architectures, downhole injection of chemicals is increasingly required to manage challenges such as scale formation or asphaltene precipitation within the wellbore. Typically chemicals are injected via a chemical injection system including an injection check valve. Because the injection valves are normally installed deep within the well, they are constantly subject to high temperatures and high pressures. The injection valves are also exposed to various chemicals having different chemical and physical characteristics. These harsh working conditions could cause leakage or total failure of an injection valve having a seal made of polymeric materials because polymeric materials may lose their mechanical strength at elevated temperatures, have low wear/impact resistance or have poor chemical stability to injection fluids. Thus, the art is receptive to alternative injection valves that have good pressure resistance, thermal resistance, and chemical resistance.